When cavitation occurs, the vapor bubble bursts continuously in the high-pressure zone (if it is caused by internal reflux, you can hear irregular crackling noises in the pump), accompanied by high-intensity impact sound , Resulting in unacceptable noise and vibration, damage to the impeller and pump casing, and degradation of pump performance (such as reduced flow, reduced head, etc.).
Internal reflux is the main and common cause of pump cavitation, and the suction specific speed is an index to measure the suction performance of a centrifugal pump, and it is also an evaluation scale for the sensitivity to internal reflux.
According to the basic principle of cavitation, the higher the suction specific speed, the better the anti-cavitation ability of the pump, but the lower the efficiency of the pump.
The reason why a limit value is given for the suction specific speed is because each pump has a flow operating range. Within the pump's operating range, the acceptable vibration characteristics are closely related to the suction specific speed. For a pump with a high suction specific speed, when it runs near the highest efficiency point, the flow of the medium at the impeller inlet is relatively stable and uniform; when the flow is insufficient and the pump deviates from the highest efficiency point, it will be at the suction port and the impeller. The discharge port produces internal reflux and increases energy loss, resulting in a significant increase in pump vibration.
Cavitation phenomenon is a major failure during the use of the pump. In the light of the damage to the components, the pump body will be damaged. Whether it is a long-axis deep well pump, an electric fire pump, a diesel fire pump and other equipment, it must be avoided. You should choose the appropriate type of pump. Equipment matching, and then installation, commissioning, and maintenance should be done to prevent cavitation as much as possible.